Superheater



Patented Feb. 6, 1945 SUPERHEATER Frederick S. Beach, Plainfield, N. J., assgnor to Foster-Wheeler Corporation, New York, N. Y., a corporation of New York application october s, 1942, serial No. 461,380 12 claims. (orizz-485) This invention relates to the superheatingof vapors,'and more particularly pertains to separately fired superheaters.

The invention provides a separately red vapor superheater having a plurality of/ sections connected for series flow of vapor therethrough, at

least one section being a radiant heat absorbing section which is disposed between convection heat absorbing sections with respect to the pathof flow of the vapor` being superheated. Superheaters embodying the invention possess numerous advantages which will be mentioned Vhereinafter.

The invention will be understood from `the following description when considered in connection with the accompanying drawing forming a part thereof, and in which the single gure is alongitudinal vertical sectional view of a separately iired steam superheater embodying the invention.

Referring to the drawing, the separately red superheater illustrated, has a setting comprising a front wall I0, a 'rear wall Il, a roof I2, a iloor I3, a side wall `I4, and an opposite side wall not shown. A bridge Wall I divides the/interior of the setting into a lfurnace I6 anda convection heating chamber between the rear wall and the bridge wall, y'the heating chamber being divided into three gas passes by baille means and I8. One or more burners I9 which iire the furnace I6 are disposed in the lower portion of the front wall I0. Air is supplied to these burners through an air duct 20.

In the form of the invention shown, the superheater has three convection sections 2|, 22 and 23 and one radiant heating section designated 24. These sections are connected for series flow of the steam therethrough, with the radiant section 24 connected between convection sections 2| and 22. Each convection section is arranged for one pass of the steam therethrough, and the radiant section is arranged for two passes of the steam therethrough.

Steam enters inlet header 25 of convection section 2| which is disposed adjacent rear wallll of the third gas pass of the convection heating chamber, and after passing through the tubes of section 2|, ows into outlet header 26, from which it ows through tubes 21 disposed along the roof of the setting above the convection secV tions 22 and 23 and along the roof of the furnace I6 and the upper portion of front wall l0 to intermediate header 23, from which the steam ows through tubes 29 to the inlet header 30 of the 30, the steam flows through section 22 to header 3| and therefrom through the tubes of convection section 23 to the outlet header 32 of the superheater. Gases produced by the one or more burners I9, flow through furnace I6 in radiant heat absorbing relationship with the tubes of the radiant section 24 and over the top of bridge wall I5, over the tubes of section 23 in a downward and rearward direction, thenceupw'ardly and rearwardly over the tubes of section 22, and thereafter over the top of baille I8 and downwardly and rearwardly over section 2|, and from the setting through outlet 33. The tubes of the radiant heat absorbing sectionA 24 are disposed substantially outof the path of the products of rcombustion owng through the setting.

' The inlet and outlet headers of the front section are enclosed ina removable housing 34, and intermediate header 28 of the radiant section 24 is enclosed in a removable housing 35. The portion of roof |2 below the housing 34 is also removable second convection section 22. From inlet header to yprovide access to the convection sections of the superheater.

With this arrangement, with the radiant heat absorbing surface in the furnace, the unit may be operated with lower excess air than ordinarily, while still maintaining reasonable furnace and gas temperatures entering the convection sections, thereby increasing the overall efllciency of the superheater. The location of the radiant heating section between convection heating sec'- tions, permits operation of the superheater without obtaining high steam temperatures in the radiant heating section, thus eliminating the necessity for the use of expensive alloy tubing in the radiant heatingnsection, and in some instances making it possible to eliminate alloy tubing entirely, depending upon the final Vsteam temperature which the unit is required'to deliver. The inlet or first convection section 2| is disposed in the coolest gas zone, thus increasing the eiliciency of the unit. The steam flow through all of the convection sections is countercurrent to the gas flow in all of the gas passes.

With the radiant heating elements extending above convection sections 22 and 23, as shown, it is possible to employ a simple roof construction which eliminates anycomplicated suspended arch in this location and permits relatively easy removal of the convection elements. The use of headers for connecting the convection and radiant heating sections, tends to cause a thorough mixing of the steam between each section,thus

providing even distribution of steam to the superf overheating due to stratication of the steam now.

Changes may be made in the form, location andl relative arrangement of the several parts of the superheater disclosed without departing from the principles of rthe invention. In viewthereof,

it will be understood that the invention is not to y l be limited exceptingby the scope of the appended l claims. v

What is claimed is: 1. A separately fired vapor superheater having bustion in the setting, and a plurality of heat absorbing sectionsin the setting ,connected for series now of vapor therethrough, at least one section being locatedto absorb radiant-heat from a setting, means for producing productsv of comsaid products'of combustion, other sections being 1 disposed to absorb convection heat from said products of combustion, theiat least one radiant section being disposed between convection sec- Y tions with `respect to the flow of the vapor to be superheated, the convection sections and the at least one radiant section disposed therebetween being positioned in relation to the ow of the l sagethereof into the radiant section.

2. A separately fired vapor superheater having a setting, means for producing products of combustion in the setting, a plurality of tubular heat absorbing sections in the setting, at least one section being located to absorb radiant heat from said products of combustion, other sections being disposed to absorb convection heat from said ,y

products vof combustion, and a header vfor connecting each pair of succeeding sections in the I path of flow of the vapor to be superheated', the

at least one radiant section being disposed between convection sections with respect to the flow of the vapor to be superheated, the convection sections and the at least one radiant section disposed therebetween being positioned in relation to the flow of gases of combustion so that said gases ow over one of the convection sections after owing in heat exchange relationship with the radiant section and the other convection section, said one convection section receiving vapor 1 prior to passage thereof into the radiant section.

3. A separately fired vapor superheater having absorbing sections in the setting connected for l' series flow of vapor therethrough, at leastl one 1 section being located to absorb radiant heat from said products of combustion, other sections being disposed to absorb convection heat from said l products of combustion, the `at least one radiant section being disposed between convection sections with respect to the flow of the vapor to be superheated and in heat exchange relationship with the products of combustion of highest temheated being delivered to a convection section located in heat exchange relationship with the 4. A separately red vapor superheater comprising alsetting, a furnace in the setting, means i for ring the furnace, a radiant vapor superheating section in the furnace, and a plurality of convection vapor superheater sections in the seta setting, means for producing products of com- 3 bustion in the setting, and a plurality of heat l perature in the setting, the vapor 'to be superi products of combustion of lowest temperature in I l the setting.

ting outside said furnace, said convection superheater sections being connected for series ow of vapor therethrough with the radiant section connected `between conve'ctionsections with respect to the now of ,vapor to be superheated, the convection section and the radiant section disposed "therebetween being positioned in relation to the flow of the gases off combustion so that said gases now over one vof the convection sections after 'flowing in heat exchange relationship with' the radiant section and thefother convection section, said one convection section receiving vapor prior to passage thereof into the radiant section.

l5. A separately flredvapor superheater comprising a'setting, a furnace in the setting, means for firing the furnace, a radiant vapor superheater section in the furnace, the vsetting having an outlet vfor the products-of combustion produced in the furnace, means providing a plurality of Ipasses for the products of vcombustion flowing from the furnace to lsaidoutlet, land a convection vapor 'superheater section in each of said passes,

said superheater sections being connected for series flow of vapor therethrough with the radiant section connected between convection sections with respect lt0 the flow of vapor to be superheated, the convection section and the radiant section disposed `therebetween being 'positioned in relation to the flow of the gases of combustion so that said gases owover one of the convection sections after flowing in heat exchange relationship with the radiant section and the other convection section, said one convection section receiving vapor prior t0 passage thereof into the radiant section. y

` 6. A separately red vapor superheater comprising a setting, a furnacei'nthe setting, means for firing the furnace, a radiant vapor superheater section in the furnace, the setting having an outlet for the products of combustion produced in the furnace, means providing a plurality of passes for the products 'of combustion flowing from the furnace to said outlet, and a convection vapor superheater section in each of said passes, said superheater sections being connected for series flow of vapor therethrough with the radiant section connected between convection sections heater section in the furnace, the setting having an outlet for the productsof combustion produced in the furnace, means providing a plurality lof passes for the products of combustion flowing from the furnace to said outlet, and a convection vapor superheater section in each of said passes, said superheater sections being connected by headers for series flow of vapor therethrough with the radiant section connected between convection sections with respect to the flow of vapor tobe superheated, the convection section and the radiant section disposed therebetween being positioned vin relation to the flow of the gases of combustion so that said gases flow over one of the convection sections after flowing in heat exchange relationship with the radiant section and the other convection section, said one convection section receiving vapor prior to passage thereof into the radiant section.v

8. A separately fired vapor superheater comprising a'setting, a bridge wail in the setting dividing the interior thereof into a furnace and a heating chamber, means for firing the furnace,

baiie means for dividing the hea-ting chamber into a plurality of gas passes, the setting having a gas vection 'superheater section in each of a plurality of said gas passes, a. radiant superheater section having tubular members disposed adjacent at least one wall of the furnace, the vapor to be superheated being delivered to the convection section in the last gas pass, means for connecting said section in the last gas pass to the radiant section, and means for connecting said radiant section to a convection section in another of said gas passes.

9. A separately fired vapor superheater comprising a setting, a bridge wall in the setting.

dividing the interior thereof into a furnace and a heating chamber, means for firing the furnace, bailie means for dividing the heating chamber into a plurality of gas passes, the setting having a gas outlet connecting with the last gas pass, a convection superheater section `in each of a plurality of said gaspasses, a radiant superheater section having tubular members disposed adjacent at least one wall of the furnace, the vapor to be superheated being delivered to the convection section in the last gas pass, means for connecting said section in the last gas pass to the radiant section, and means for connecting said radiant section to a convection section in another of said gas passes, parts of the tubular members of the radiant section being disposed above at least one of said convection sections.

10. A separately red vapor superheater comprising a setting, a, bridge wall in the'setting dividing the interior thereof into a furnace and a heating chamber, means for firing the furnace, ba'le means for dividing the heating chamber into a plurality of gas passes, the setting having a gas outlet connecting with the last gas pass, a convection superheater section in each of a plurality of said gas passes, a radiant superheater section having tubular members disposed adjacent at least one wall of the furnace, the vapor to be superheated being delivered to the convection section in the last gas pass, a header for outlet `connecting with the last gas pass, a conthe radiant section, and a header for connecting said radiant section to a convection section in vanother of said gas passes.

.into three gas passes, the setting having a gas outlet connecting with the last gas pass, a convection superheater section in each gas pass, a radiant superheater section having tubular members disposed adjacent the roof of the furnace, the'vapor to be superheated being delivered to the convection section in the last gas pass, a header for connecting the section in the last gas pass to the radiant section, a header for connecting the radiant section to the convection section in the second gas pass, and a header for connecting the convection section last mentioned to the convection section in the first gas pass.

12.-A separately iiredvapor superheater comprising a setting, a bridge wall in the setting dividing the interior thereof into a furnace and a heating chamber, means for firing the furnace, bafe means for dividing the heating chamber into three gas passes, the setting having a gas outlet connecting with the last gas pass, a convection superheater section in each gas pass, a radiant superheater section having tubular mem'- bers disposed adjacent the roof of the furnace, the vapor to be superheated beingdelivered to the convection section in the last gas pass, a header for connecting the section in the last gas pass to the radiant section, a header for connect-A ing the radiant section to the convection section in the second gas pass, and a header for connecting the convection section last-mentioned to the convection section in the first gas pass, parts of the tubular members of the radiant section being disposed above the convection sections in the first and second gas passes.

FREDERICK S. BEACH.

connecting said section in the last gas pass tov 

